The present invention relates to fly-height of a read head, and in particular, to fly-height touchdown detection circuits and methods.
Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Hard disk drives have increased in reliability and storage capacity. The read head fly-height influences the density at which the hard disk information may be read hack. The closer the read head is to the platter, the more information may be programmed per unit area of the platter surface. Also the closer the read head is to the platter, the more likely the read head may touchdown on the platter. The read head touchdowns may decrease the long term reliability of the hard disk drive.
A hard drive includes a head slider suspension assembly to place the read head above the hard disk drive. The platter surface of the hard disk is moving at a high rate of speed and the slider of the head slider assembly is hovering above the surface of the platter. A thin layer or air called an air bearing allows the slider to maintain a fly-height between the platter surface and the read head. The fly-height depends on the air pressure associated with the air bearing. Taking into account the required reliability for the hard disk drive, the tolerance of the fly-height restricts the possible hard disk drive capacity.
Thus, there is a need for improved hard disk drives. The present invention solves these and other problems by providing fly-height touchdown detection and circuits.